CN113480721B

CN113480721B - Process for producing copolycarbonates having improved properties, copolycarbonates and use thereof

Info

Publication number: CN113480721B
Application number: CN202110906830.0A
Authority: CN
Inventors: 黎雷; 王磊; 曾伟; 魏志涛; 李凤闯; 丁可; 隋东武; 李强
Original assignee: Wanhua Chemical Group Co Ltd
Current assignee: Wanhua Chemical Group Co Ltd
Priority date: 2021-08-09
Filing date: 2021-08-09
Publication date: 2022-11-08
Anticipated expiration: 2041-08-09
Also published as: CN113480721A

Abstract

The invention relates to a preparation method of copolycarbonate with improved performance, copolycarbonate and application thereof, wherein BPTMC and BPA are used as raw materials to prepare copolycarbonate containing structural units of a general formula (I), and the preparation method is characterized in thatThe raw material BPTMC contains 1-5000ppm of bisphenol with a structure shown in a formula (II). According to the copolycarbonate prepared by the method, the content of the hydrogen chloride catalyst and the like is controlled in the raw material synthesis process, so that the impurity content in a formed product can be effectively reduced, the thermal degradation or the thermo-oxidative degradation of the polycarbonate caused by the phenolic monomers when the product is exposed to a high-temperature load is avoided, and the mechanical, thermal and optical properties of the polycarbonate are optimized.

Description

Process for preparing copolycarbonates with improved properties, copolycarbonates and their use

Technical Field

The invention relates to the technical field of polycarbonate copolymers, in particular to a preparation method of copolycarbonate with improved performance, the copolycarbonate and application thereof.

Background

With the continuous expansion of domestic polycarbonate production capacity, the market gradually becomes saturated. However, in special fields of application, higher demands are made on the properties of polycarbonates, and polycarbonates having special properties are accordingly produced. By adjusting the types and molar ratios of the comonomers, special polycarbonates with different properties appear.

By copolymerizing 1, 1-bis- (4-hydroxyphenyl) -3, 5-trimethylcyclohexane (BPTMC) and bisphenol A (BPA), polycarbonate with higher heat resistance can be obtained and can be applied to scenes under high-temperature load, such as the field of vehicle lamps. However, during the use, the molded part of the special polycarbonate is found to have reduced comprehensive properties, such as embrittlement, reduced heat resistance, yellowing of the surface of the molded part, and the like, along with the prolonging of the use time. Therefore, the improvement of the preparation method of the special polycarbonate is beneficial to improving the corresponding service performance and prolonging the service life.

Chinese patent CN102971360B describes an improved method for preparing heat-resistant polycarbonate containing 1, 1-bis- (4-hydroxyphenyl) -3, 5-trimethylcyclohexane and bisphenol a, which realizes optimization of yellowness index of a molded product by controlling the sulfur content in raw material bisphenol, but does not mention whether other properties can be improved.

Chinese patent CN107207718B describes an improved process for the preparation of heat resistant polycarbonate containing 1, 1-bis- (4-hydroxyphenyl) -3, 5-trimethylcyclohexane and bisphenol a by adding monohydroxyaryl compound to the raw material mixture to lower the melting point of the monomer mixture and further slow down the polycondensation reaction in the early stage, but without significant improvement of the corresponding performance properties of the shaped article.

Chinese patent CN101023118A describes an improved process for the preparation of heat resistant polycarbonate comprising 1, 1-bis- (4-hydroxyphenyl) -3, 5-trimethylcyclohexane and bisphenol a by controlling the sodium chlorate content in the raw sodium hydroxide solution to achieve optimization of the color of the shaped articles, but does not mention the improvement of other properties.

The applicant researches and discovers that in the synthesis process of the raw material BPTMC, 3, 5-Trimethylcyclohexanone (TMC) reacts with phenol, hydrogen chloride gas is added into a reaction system as a catalyst, and the pH value of the reaction system is controlled. When the pH value is regulated, the amount of the catalyst is not easy to control, but obviously influences the selectivity of the product, and if the amount exceeds 20mol% (based on the amount of the substance of the reactant TMC), the bisphenol compound with the structure of the formula (IV) is easy to react.

The applicant discovers that the control of the index of the raw material is a key factor when analyzing the whole preparation process, and particularly plays a key role in improving the comprehensive performance of the special polycarbonate, particularly in resisting heat, yellowing and the like by controlling the content of the bisphenol compound in the formula (IV) in the raw material, thereby completing the invention.

Disclosure of Invention

In order to solve the problems in the prior art, the invention provides a preparation method of copolycarbonate with improved performance, which improves the comprehensive performance of the special polycarbonate by controlling the content of bisphenol compounds in the formula (IV) in raw materials, prolongs the service life and is beneficial to widening the application of the special polycarbonate in more fields.

It is another object of the present invention to provide such copolycarbonates with improved properties.

It is a further object of the present invention to provide the use of copolycarbonates having improved properties.

In order to realize the purpose, the invention adopts the following technical scheme:

a preparation method of copolycarbonate with improved performance takes dihydroxydiphenyl cycloalkane with a structure shown in a formula (I) and a diphenol compound with a structure shown in a formula (V) as raw materials to prepare the copolycarbonate by a phosgene interfacial polycondensation method or a melt transesterification method, wherein the raw materials also contain 1-5000ppm of bisphenol with a structure shown in a formula (II);

wherein R is ¹ 、R ² 、R ³ 、R ⁴ Each independently selected from H, halogen, C ₁ ～C ₁₀ Alkyl of (C) ₅ ～C ₆ Cycloalkyl or C ₆ ～C ₁₀ Any one of the aryl groups of (a); r ⁵ 、R ⁶ 、R ⁷ Each independently selected from H or C ₁ ～C ₁₀ Alkyl groups of (a); r ⁸ 、R ⁹ 、R ¹⁰ Each independently selected from H or C ₁ ～C ₈ The alkyl group of (1).

In a preferred embodiment, the bisphenol compound of formula (I) has the formula:

in a preferred embodiment, the bisphenol compound of formula (II) has the formula:

in a preferred embodiment, the diphenol compound of formula (V) is bisphenol A.

In a preferred embodiment, the content of the bisphenol compound of the structure of formula (IV) in the starting material is controlled to be 1 to 500ppm.

In a preferred embodiment, the copolycarbonate is a copolymer of BPTMC and bisphenol a of the structure of formula (III), wherein the molar ratio of BPTMC to bisphenol a is from 1 to 99, preferably from 10 to 70, more preferably from 30 to 60.

On the other hand, the copolycarbonate having improved properties obtained by the above-mentioned production method has a weight average molecular weight of 5000 to 600000, preferably 15000 to 70000, more preferably 20000 to 50000.

In a specific embodiment, the copolycarbonate has a flexural strength of 50 to 200MPa, an elongation at break of 50 to 200%, a Vicat temperature of 150 to 250 ℃, a light transmittance of 80 to 92%, and a haze of 0.3 to 10%.

In a specific embodiment, at least any one selected from the group consisting of a mold release agent, a flow aid, a heat stabilizer, a hydrolysis stabilizer, an antioxidant, a UV absorber, a flame retardant, an antistatic agent, a pigment, or a reinforcing filler is further contained in an amount of 0 to 5wt%, preferably 0 to 2.5wt%, more preferably 0 to 2wt%, based on the total weight of the copolycarbonate.

In another aspect, the copolycarbonate with improved properties is used in the field of vehicle lamps, lamp bead lenses or medical devices.

Compared with the prior art, the invention has the following beneficial effects:

the copolycarbonate with improved performance of the invention can effectively reduce the impurity content in a formed product by controlling the content of the bisphenol compound with the structure of the formula (II), especially the structure of the formula (IV) in the raw material to be 1-5000ppm, especially 1-500ppm, and can avoid the phenolic monomer inducing thermal degradation or thermal-oxidative degradation of the polycarbonate when the product is exposed to high-temperature load (such as extrusion granulation).

The copolycarbonate disclosed by the invention has a small content of the formula (IV), so that yellowing of a sample in an extrusion or injection molding processing process can be avoided, and various properties of a product are further influenced. The yellowing of the surface of the product caused by the oxidation of the formula (IV), which may cause the deterioration of optical properties such as the reduction of light transmittance and the increase of haze, can be effectively avoided; meanwhile, the biological toxicity caused by micro release of the phenolic monomers in the product is also reduced.

The copolycarbonate of the invention can avoid the degradation of the polymer caused by overhigh content by controlling the content of the formula (IV) in a certain range, thereby further reducing the performance, and simultaneously, the content is controlled to be more than 1ppm, thereby ensuring that the performance of the polymer is not obviously reduced and reducing the cost of the post-treatment process.

Detailed Description

The following examples will further illustrate the method provided by the present invention in order to better understand the technical solution of the present invention, but the present invention is not limited to the listed examples, and should also include any other known modifications within the scope of the claims of the present invention.

Preparing a copolycarbonate comprising a structural unit of formula (I) according to a phosgene interfacial polycondensation method or a melt transesterification method, wherein the copolycarbonate is prepared by controlling the content of a bisphenol having a structure of formula (II) in raw materials to be in the range of 1 to 5000ppm.

Wherein R is ¹ 、R ² 、R ³ 、R ⁴ Each independently selected from H, halogen, C ₁ ～C ₁₀ Alkyl of (C) ₅ ～C ₆ Cycloalkyl or C ₆ ～C ₁₀ Any one of the aryl groups of (a); r is ⁵ 、R ⁶ 、R ⁷ Each independently selected from H or C ₁ ～C ₁₀ Alkyl of R ⁸ 、R ⁹ 、R ¹⁰ Each independently selected from H orC ₁ ～C ₈ Alkyl group of (1). Specifically, the C ₁ ～C ₁₀ The alkyl group of (A) may be, for example, methyl, ethyl, propyl, isopropyl, the C being ₅ ～C ₆ Cycloalkyl of (C) can be, for example, cyclopentyl, C ₆ ～C ₁₀ Aryl of (D) may be, for example, phenyl, C ₁ ～C ₈ The alkyl group of (b) may be, for example, a methyl group, an ethyl group, a propyl group, an isopropyl group, but is not limited thereto. In particular, when R ¹ 、R ² 、R ³ 、R ⁴ Are all selected from H, R ⁵ 、R ⁶ 、R ⁷ When all are selected from methyl, the compound with the structure of the formula (I) is 1, 1-bis- (4-hydroxyphenyl) -3, 5-trimethylcyclohexane (BPTMC) with the structure of the formula (III), and the dihydroxy diphenyl cycloalkane is also one of the most common synthetic raw materials of special polycarbonate polymers.

When R is ⁸ 、R ⁹ 、R ¹⁰ When all the bisphenol compounds are selected from methyl, the bisphenol compound with the structure of the formula (II) is the bisphenol compound with the structure of the formula (IV). That is, particularly, the present invention comprises a bisphenol having the structure of formula (IV) in an amount of 1 to 5000ppm for preparing a copolycarbonate, wherein the content of formula (IV) is measured by a liquid chromatography method known to those skilled in the art, and preferably, the content of bisphenol having the structure of formula (IV) is controlled at a level of 1 to 500ppm.

The key point of the invention is that the bisphenol compound with the structure of formula (IV) is generated in the synthesis process of the raw material BPTMC, and the content of the bisphenol compound with the structure of formula (IV) in the raw material influences the comprehensive performance of the finally prepared copolycarbonate. The invention optimizes the selectivity of the product by controlling the catalyst dosage or pH value and other process conditions in the synthesis process of the raw material BPTMC, so that the content of bisphenol generating the structure of formula (IV) is controlled at the level of 1-5000ppm, preferably at the level of 1-500ppm.

The copolycarbonates prepared according to the invention further comprise as comonomers diphenol compounds of the formula (V)

Wherein R is ¹ 、R ² 、R ³ 、R ⁴ Each independently selected from H, halogen, C ₁ ～C ₁₀ Alkyl of (C) ₅ ～C ₆ Cycloalkyl or C ₆ ～C ₁₀ Any one of the aryl groups of (a); specifically, the C ₁ ～C ₁₀ The alkyl group of (A) may be, for example, methyl, ethyl, propyl, the C ₅ ～C ₆ Cycloalkyl of (C) can be, for example, cyclopentyl, C ₆ ～C ₁₀ The aryl group of (a) may be, for example, a phenyl group, but is not limited thereto. Preferably, R is ¹ 、R ² 、R ³ 、R ⁴ When both are selected from H, the diphenol compound of formula (V) is bisphenol A, which is one of the other starting materials for copolycarbonates.

Preferably, the preparation method of the present invention comprises copolymerizing 1, 1-bis- (4-hydroxyphenyl) -3, 5-trimethylcyclohexane (BPTMC) having a structure of formula (III) with bisphenol A (BPA) by a phosgene interfacial polycondensation method or a melt transesterification method to obtain a polycarbonate having higher heat resistance, wherein the bisphenol content of the structure of formula (IV) in the raw material is controlled at a level of 1 to 5000ppm, including, but not limited to, for example, 1ppm, 5ppm, 10ppm, 50ppm, 100ppm, 300ppm, 500ppm, 800ppm, 1000ppm, 1500ppm, 2000ppm, 2500ppm, 3000ppm, 3500ppm, 4000ppm, 4500ppm, 5000ppm, preferably at a level of 1 to 500ppm.

The copolycarbonate prepared in the invention, wherein the molar ratio of the BPTMC having the structure of formula (III) to bisphenol a is 1:99. 10: 90. 20:80. 30:70. 40:60. 50: 50. 60: 40. 70:30. 80:20. 90: 10. 99:1, preferably 10.

In the present invention, the copolycarbonate according to the present invention can be prepared by a phosgene interfacial polycondensation method or a melt transesterification method which are well known to those skilled in the art, and the present invention is not limited thereto, and can be referred to the prior art, except that the bisphenol having the structure of formula (IV) as a raw material is controlled to a level of 1 to 5000ppm.

The copolycarbonates prepared in the present invention have a weight average molecular weight of 15000 to 60000, including, for example, but not limited to, 15000, 20000, 25000, 30000, 35000, 40000, 45000, 50000, 55000, 60000, preferably 20000 to 40000, more preferably 25000 to 35000.

The copolycarbonates of the present invention may additionally contain various conventional additives conventionally added to thermoplastic resins as required for processability. The proportion of additives is from 0 to 5% by weight, including, for example, but not limited to, 0% by weight, 0.5% by weight, 1% by weight, 1.5% by weight, 2% by weight, 2.5% by weight, 3% by weight, 3.5% by weight, 4% by weight, 4.5% by weight, 5% by weight, preferably from 0 to 2.5% by weight, particularly preferably from 0 to 2% by weight, based on the total weight of the copolycarbonate. Optional conventional additives include, for example: any one or more of mold release agents, flow aids, heat stabilizers, hydrolytic stabilizers, antioxidants, UV absorbers, flame retardants, antistatic agents, pigments, reinforcing fillers, but are not limited thereto and are well known to those skilled in the art and are intended to be within the scope of the present invention.

The copolycarbonates of the invention and the above-described additives can be compounded to produce a composition. Can be prepared by the following method: the components are mixed in a known manner and melt-compounded and melt-extruded at temperatures of from 250 ℃ to 330 ℃ in customary apparatuses such as internal mixers, extruders and twin-screw kneaders, and granulated by means of a granulator.

The copolycarbonate of the invention can change the bending strength within the range of 60-150MPa, the elongation at break within the range of 85-140%, the Vicat temperature within the range of 130-230 ℃, the light transmittance within the range of 85-92%, and the haze within the range of 0.3-6% according to the different proportions of the BPTMC and the bisphenol A monomers.

The copolycarbonates according to the invention or the compositions thereof can be used for the production of shaped parts of any type, which can be produced by injection molding, extrusion and blow molding processes, such as those described above with reference to the prior art.

Preferred applications of the copolycarbonates or compositions thereof according to the invention are transparent/translucent or colored injection-molded parts, extrudates, such as sheets, film laminates, profiles, semi-finished products, and cast films made of high molecular weight polycarbonate.

The invention is further illustrated, but not limited, by the following more specific examples.

The following examples and comparative examples used the following sources of raw materials:

BPTMC, aladdin reagent Co., ltd., purity > 98%, formula (IV) content 6000ppm;

3, 5-Trimethylcyclohexanone (TMC), allantin reagent, inc., purity > 98%;

phenol, aladdin reagent, inc., purity > 98%;

bisphenol A, lihuayiweiyuan chemical Co., ltd., purity > 98%.

The prepared copolycarbonate resin was subjected to a performance test by the following method:

flexural strength is measured according to ISO178, elongation at break is measured according to ISO527, vicat temperature is measured according to ISO306, and light transmittance and haze are measured according to ISO13468-2, ISO14782, respectively.

Weight average molecular weight, determined by volume exclusion gel chromatography after pre-calibration with PS or polycarbonate calibration substances.

The bisphenol content of the structure of formula (IV) is determined by liquid chromatography methods known to those skilled in the art.

Preparation example 1

The raw material BPTMC was synthesized by a laboratory and the content of the bisphenol compound of the structure of formula (IV) was measured by a liquid chromatograph.

The preparation method comprises the following steps: 700g (5 mol) of TMC is weighed into a 5L four-neck flask, then 2350g (25 mol) of phenol is added into the four-neck flask, and hydrogen chloride gas is continuously introduced into the four-neck flask to carry out reaction in a constant-temperature water bath at the temperature of 35 ℃. During the reaction, the pH of the reaction solution was continuously monitored. After about 8h of reaction, the introduction of hydrogen chloride gas was stopped and an appropriate amount of 5% NaOH solution was added to the flask until the pH of the solution was close to 7.

Subsequently, the reaction solution was filtered, and the filter cake was weighed. A5L four-necked flask was taken, and the cake was transferred to a bottle, and toluene of an equal mass and pure water of a half mass were added thereto, followed by heating and refluxing at 95 ℃. After the reflux time was about 2h, heating was stopped, and the solution was filtered using a buchner funnel while waiting for the temperature of the solution in the flask to decrease to 40 ℃. In the filtering process, toluene and water can be used for repeatedly washing the filter cake for 2-3 times, and then the filter cake is heated and dried to obtain the raw material BPTMC.

The source of the raw materials in the examples and comparative examples will now be described as shown in the following table:

as shown in the table above, the content of the compound with the structure of formula (IV) in the raw material BPTMC can be controlled by changing the introduction amount of the catalyst.

Example 1

A copolycarbonate prepared from formula (III), bisphenol a, was synthesized in a molar ratio of 99.

306.9g (0.99 mol) of the compound of the formula (III), 2.28g (0.01 mol) of bisphenol A, 222.79g (1.04 mol) of diphenyl carbonate and 0.01g (2.5X 10 mol) ^-4 mol) sodium hydroxide was charged into a reactor equipped with a stirring and distilling device, and heated to 160 ℃ under normal pressure over 0.5 hour to melt it. Thereafter, the temperature was raised to 210 ℃ over 1 hour, and stirring was performed. Then, the pressure was adjusted to 2.5KPa for 30 minutes, and the ester exchange reaction was carried out by maintaining the pressure at 210 ℃ and 2.5KPa for 30 minutes. Then, the temperature was raised to 270 ℃ at a rate of 30 ℃/hr, and the temperature was maintained at 270 ℃ and 2.5KPa for 30 minutes. Then, the temperature was adjusted to 1KPa for 10 minutes, and the mixture was held at 270 ℃ and 1KPa for 1 hour. The pressure was reduced to 133Pa or less for 30 minutes, and the mixture was stirred at 270 ℃ for 20 minutes at 133Pa or less to conduct polymerization. After the reaction, 2 times mole of butyl benzoate was added to deactivate the catalyst, and the catalyst was discharged from the bottom of the reaction tank under pressure of nitrogen, cooled in a water tank, and cut with a pelletizer to obtain pellets. ObtainedCopolycarbonate resin, no. A1, weight average molecular weight 31659.

Wherein, in the bisphenol compound with the structure of the formula (III), the content of the formula (IV) is 953ppm.

Example 2

Monomer content and Synthesis procedure A copolycarbonate resin, no. A2, weight average molecular weight 32325 was synthesized in accordance with example 1.

Wherein, in the bisphenol compound with the structure of the formula (III), the content of the formula (IV) is 452ppm.

Example 3

A copolycarbonate prepared from formula (III), bisphenol A was synthesized in a molar ratio of 1.

3.1g (0.01 mol) of the compound of the formula (III), 225.72g (0.99 mol) of bisphenol A, 222.79g (1.04 mol) of diphenyl carbonate and 0.01g (2.5X 10-4 mol) of sodium hydroxide were charged into a reactor equipped with a stirrer and distillation apparatus, and they were heated to 160 ℃ under normal pressure over 0.5 hour to be melted. Thereafter, the temperature was raised to 210 ℃ over 1 hour, and stirring was performed. Then, the pressure was adjusted to 2.5KPa for 30 minutes, and the ester exchange reaction was carried out by maintaining the pressure at 210 ℃ and 2.5KPa for 30 minutes. Then, the temperature was raised to 270 ℃ at a rate of 30 ℃/hr, and the temperature was maintained at 270 ℃ and 2.5KPa for 30 minutes. Then, the temperature was adjusted to 1KPa for 10 minutes, and the mixture was held at 270 ℃ and 1KPa for 1 hour. The pressure was reduced to 133Pa or less for 30 minutes, and the mixture was stirred at 270 ℃ for 20 minutes at 133Pa or less to conduct polymerization. After the reaction, 2 times the amount of the catalyst was added to deactivate the catalyst by adding butyl benzoate in an amount of 2 moles, discharged from the bottom of the reaction tank under nitrogen pressure, cooled in a water tank, and cut with a pelletizer to obtain pellets. The resulting copolycarbonate resin was numbered A3 and had a weight-average molecular weight of 32101.

Wherein, in the bisphenol compound with the structure of the formula (III), the content of the formula (IV) is 1.2ppm.

Example 4

A copolycarbonate prepared from formula (III), bisphenol A was synthesized in a molar ratio of 30.

A copolymerized polycarbonate resin, no. A4, weight-average molecular weight 31246 was synthesized with reference to example 1, except that 93g (0.3 mol) of the compound having a structure of the formula (III) and 159.6g (0.7 mol) of bisphenol A were used.

Wherein, in the bisphenol compound with the structure of the formula (III), the content of the formula (IV) is 982ppm.

Example 5

A copolycarbonate prepared from formula (III), bisphenol a, was synthesized at a molar ratio of 30.

Monomer content and Synthesis procedure A copolycarbonate resin, no. A5, weight average molecular weight 32754 was synthesized in accordance with example 4.

Wherein, in the bisphenol compound with the structure of the formula (III), the content of the formula (IV) is 503ppm.

Example 6

Monomer content and Synthesis procedure A copolycarbonate resin, no. A6, weight average molecular weight 31997 was synthesized in accordance with example 4.

Wherein, in the bisphenol compound with the structure of the formula (III), the content of the formula (IV) is 2.6ppm.

Example 7

A copolycarbonate prepared from formula (III), bisphenol A, was synthesized in a molar ratio of 80.

A copolycarbonate resin, no. A7, weight average molecular weight 33076 was synthesized in accordance with example 1 except that 248g (0.8 mol) of the compound having the structure of the formula (III) and 45.6g (0.2 mol) of bisphenol A were used.

Wherein, in the bisphenol compound with the structure of the formula (III), the content of the formula (IV) is 989ppm.

Example 8

A copolycarbonate prepared from formula (III), bisphenol A was synthesized in a molar ratio of 80.

Monomer content and Synthesis procedure A copolycarbonate resin, no. A8, having a weight average molecular weight of 32215 was synthesized in accordance with example 7.

Wherein, in the bisphenol compound with the structure of the formula (III), the content of the formula (IV) is 582ppm.

Example 9

Monomer content and Synthesis procedure A copolycarbonate resin, no. A9, weight average molecular weight 32379 was synthesized in accordance with example 7.

Wherein, in the bisphenol compound with the structure of the formula (III), the content of the formula (IV) is 1ppm.

Example 10

Monomer content and Synthesis procedure A copolycarbonate resin, no. A10, weight average molecular weight 33259 was synthesized in accordance with example 7.

Wherein, in the bisphenol compound with the structure of formula (III), the content of formula (IV) is 2351ppm.

Example 11

Monomer content and Synthesis procedure A copolycarbonate resin, no. A11, weight average molecular weight 32571, was synthesized in reference to example 7.

Wherein, in the bisphenol compound with the structure of formula (III), the content of formula (IV) is 3284ppm.

Example 12

A copolycarbonate prepared from bisphenol A of formula (III) was synthesized in a molar ratio of 20.

62g (0.2 mol) of the compound having the structure of the formula (III), 182.4g (0.8 mol) of bisphenol A, 222.79g (1.04 mol) of diphenyl carbonate and 0.01g (2.5X 10-4 mol) of sodium hydroxide were charged into a reactor equipped with a stirrer and a distillation apparatus, and they were heated to 160 ℃ under normal pressure over 0.5 hour to be melted. Thereafter, the temperature was raised to 210 ℃ over 1 hour, and stirring was performed. Then, the pressure was adjusted to 2.5KPa for 30 minutes, and the ester exchange reaction was carried out by maintaining the pressure at 210 ℃ and 2.5KPa for 30 minutes. The temperature was raised to 270 ℃ at a rate of 30 ℃ per hour, and the temperature was maintained at 270 ℃ and 2.5KPa for 30 minutes. Then, the temperature was adjusted to 1KPa for 10 minutes, and the mixture was maintained at 270 ℃ and 1KPa for 1 hour. The pressure was further reduced to 133Pa or less for 30 minutes, and the mixture was stirred at 270 ℃ and 133Pa or less for 20 minutes to effect polymerization. After the reaction, 2 times mole of butyl benzoate was added to deactivate the catalyst, and the catalyst was discharged from the bottom of the reaction tank under pressure of nitrogen, cooled in a water tank, and cut with a pelletizer to obtain pellets. The resulting copolycarbonate resin had number A12 and weight-average molecular weight of 33206.

Wherein, in the bisphenol compound with the structure of the formula (III), the content of the formula (IV) is 4568ppm.

Comparative example 1

A copolycarbonate resin, no. D1, weight average molecular weight 32147 was synthesized in accordance with example 6, except that 93g (0.3 mol) of the compound having the structure of formula (III) and 159.6g (0.7 mol) of bisphenol A were used.

Wherein, in the bisphenol compound with the structure of the formula (III), the content of the formula (IV) is 0.1ppm.

Comparative example 2

A copolymerized polycarbonate resin, no. D2, weight-average molecular weight 32452 was synthesized with reference to example 11 except that 248g (0.8 mol) of the compound having the structure of formula (III) and 45.6g (0.2 mol) of bisphenol A were used.

Wherein, in the bisphenol compound with the structure of the formula (III), the content of the formula (IV) is 5205ppm.

Comparative example 3

A copolymerized polycarbonate resin, no. D3, weight-average molecular weight 33211 was synthesized in accordance with example 12, except that 62g (0.2 mol) of the compound having the structure of formula (III) and 182.4g (0.8 mol) of bisphenol A were used.

Wherein, in the bisphenol compound with the structure of the formula (III), the content of the formula (IV) is 6000ppm.

The results of the property tests of the copolycarbonates prepared in the above examples and comparative examples are shown in the following table:

as can be seen from the table, by reducing the content of bisphenol substance with the structure of formula (IV) in the raw material BPTMC, the bending strength, the elongation at break, the Vicat temperature and the light transmittance of the polymer are improved, and the haze is reduced. When the content of the bisphenol substance with the formula (IV) in the raw material BPTMC is lower than 1ppm, the light transmittance and haze of the product are not obviously changed, but the cost of the raw material post-treatment is obviously increased, so the content of the bisphenol substance with the formula (IV) in the raw material BPTMC is preferably controlled to be 1-5000 ppm.

While the present invention has been described in detail with reference to the preferred embodiments, it should be understood that the above description should not be taken as limiting the invention. It will be appreciated by those skilled in the art that modifications or adaptations to the invention may be made in light of the teachings of the present specification. Such modifications or adaptations are intended to be within the scope of the present invention as defined by the claims.

Claims

1. A preparation method of copolycarbonate with improved performance is characterized in that dihydroxy diphenyl cycloalkane with a structure shown in a formula (I) and a diphenol compound with a structure shown in a formula (V) are used as raw materials, and the copolycarbonate is prepared by a phosgene interfacial polycondensation method or a melt transesterification method, wherein the raw materials also contain 1-5000ppm of bisphenol with a structure shown in a formula (II);

wherein R is ¹ 、R ² 、R ³ 、R ⁴ Each independently selected from H, halogen, C ₁ ～C ₁₀ Alkyl of (C) ₅ ～C ₆ Cycloalkyl or C ₆ ～C ₁₀ Any one of the aryl groups of (a); r ⁵ 、R ⁶ 、R ⁷ Each independently selected from H or C ₁ ～C ₁₀ Alkyl groups of (a); r ⁸ 、R ⁹ 、R ¹⁰ Each independently selected from H or C ₁ ～C ₈ Alkyl groups of (a);

the structural formula of the bisphenol compound of the general formula (I) is as follows:

the structural formula of the bisphenol compound of the general formula (II) is as follows:

the diphenol compound of formula (V) is bisphenol A.

2. The method for preparing copolycarbonates having improved properties according to claim 1, wherein the content of the bisphenol compound having the structure of formula (IV) as a starting material is controlled to 1 to 500ppm.

3. The method of claim 1 or 2, wherein the copolycarbonate is a copolymer of BPTMC and bisphenol a having the structure of formula (III), wherein the molar ratio of BPTMC to bisphenol a is 1.

4. The method of claim 3, wherein the molar ratio of BPTMC to bisphenol A is 10 to 70.

5. The method of claim 4, wherein the molar ratio of BPTMC to bisphenol A is 30.

6. The copolycarbonate having improved properties obtained by the production method according to any one of claims 1 to 5, wherein the weight average molecular weight of the copolycarbonate is 5000 to 600000.

7. Copolycarbonates with improved properties according to claim 6, characterized in that the weight average molecular weight of the copolycarbonates is between 15000 and 70000.

8. Copolycarbonates with improved properties according to claim 7, wherein the weight average molecular weight of the copolycarbonates is 20000 to 50000.

9. The copolycarbonate having improved properties according to any one of claims 6 to 8, wherein the copolycarbonate has a flexural strength of 60 to 150MPa, an elongation at break of 85 to 140%, a Vicat temperature of 130 to 230 ℃, a light transmittance of 85 to 92%, and a haze of 0.3 to 6%.

10. The copolycarbonate having improved properties according to claim 9, further comprising 0 to 5wt% of at least any one selected from the group consisting of a mold release agent, a flow aid, a heat stabilizer, a hydrolysis stabilizer, an antioxidant, a UV absorber, a flame retardant, an antistatic agent, a pigment, and a reinforcing filler, based on the total weight of the copolycarbonate.

11. The copolycarbonate with improved properties according to claim 10, further comprising 0 to 2.5wt% of at least any one selected from the group consisting of mold release agents, flow aids, heat stabilizers, hydrolysis stabilizers, antioxidants, UV absorbers, flame retardants, antistatic agents, pigments, and reinforcing fillers, based on the total weight of the copolycarbonate.

12. The copolycarbonate having improved properties according to claim 11, further comprising 0 to 2wt% of at least any one selected from the group consisting of a mold release agent, a flow aid, a heat stabilizer, a hydrolysis stabilizer, an antioxidant, a UV absorber, a flame retardant, an antistatic agent, a pigment, and a reinforcing filler, based on the total weight of the copolycarbonate.

13. Use of a copolycarbonate prepared by the method according to any one of claims 1 to 5 or a copolycarbonate having improved properties according to any one of claims 6 to 12 in the field of automotive lamps, lamp bead lenses or medical devices.